File:Spider web Luc Viatour.jpg|thumb|Dew drops adhering to a spider web
File:Sticking-under-Wet-Conditions-The-Remarkable-Attachment-Abilities-of-the-Torrent-Frog-Staurois-pone.0073810.s004.ogv|thumb|thumbtime=7|Adhesion of a Rhacophorus pardalis|frog on a wet vertical glass surface.
'''Adhesion''' is the tendency of dissimilar particles or surfaces
to cling to one another (Cohesion (chemistry)|cohesion
refers to the tendency of similar or identical particles/surfaces to cling to one another). The forces that cause adhesion and cohesion can be divided into several types. The intermolecular forces responsible for the function of various kinds of stickers and sticky tape fall into the categories of chemical adhesion, dispersive adhesion, and diffusive adhesion. In addition to the cumulative magnitudes of these intermolecular forces, there are certain emergent mechanical effects that will also be discussed at the end of the article.